DE2520121A1 - PROCESS FOR THE PRODUCTION OF PHENOLS - Google Patents

Description

DR. BERG DIPL.-ING. STaPF DIPL.-ING. SCHWABE DR. DR. SANDMAIR

PATENT LAWYERS

8 MUNICH 86, POST BOX 8602 45

Dr. Berg Dipl.-Ing. Stapf and Partner, 8 Munich 86, P. O. Box 860245

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8 MUNICH 80 Mauerkircherstraße 45

May 6, 1975

Lawyer file no .: 26

BURMAH OIL TRADING LIMITED S w i η d ο n, Wiltshire / England

"Process for the production of phenols"

The present invention relates to a process for the preparation of phenols by the decomposition of aromatic organic compounds Hydroperoxides.

Phenol is produced quite generally on an industrial scale by decomposition of cumene hydroperoxide in the presence of an acid catalyst, for example sulfuric acid or perchloric acid, manufactured. It is believed that the mechanism

X / R

509848/1132

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this reaction _s when it is catalyzed by sulfuric acid j is the following:

CH ₃

0OH

H ₂ SO ₄

0
II

+ CE _x COCEL + H

As a result, the cumene hydroperoxide is protonated to form an intermediate I which loses water and see rearranged to intermediate II, which reacts with water to form phenol and acetone.

The hydroperoxide is usually obtained by the auto-oxidation of cumene (isopropylbenzene) and the latter can be done by Alkylation of benzene with propylene can be formed. Other tertiary aralkyl hydroperoxides can be used in the presence of acidic Catalysts are decomposed to form substituted phenols. For example, p-cresol can be decomposed from p-cymene hydroperoxide.

While the use of conventional acid catalysts to catalyze the decomposition of tertiary aralkyl hydroperoxides to phenols and ketones to reported yields up to

509848/1132

about 90 wt% phenol and 80 wt% ketone based on the Hydroperoxide, has not yet become a commercially viable method of performing the decomposition other hydroperoxides than tertiary aralkyl hydroperoxides considered, firstly because of the yields of formed Phenols are not commercially attractive and, secondly, undesirable levels of high molecular weight by-products using conventional acidic catalysts. For example, a yield of only 37% by weight phenol given if ethylbenzene hydroperoxide is decomposed in the presence of a catalyst such as sulfuric acid.

Another disadvantage of using conventional acidic catalysts is that it is usually necessary to to build the plant used to carry out the decomposition from corrosion-resistant materials, what can lead to high capital costs. In addition, it is generally necessary to remove the acidic catalyst or to neutralize before the decomposition products are further processed to produce phenol.

It has now been found novel catalysts for this process, the use of which enables the yields of Phenols or substituted phenols from secondary aralkyl

50984 8/1132

2 5? η 121

to increase hydroperoxides up to a percentage that this synthetic route to the production of phenols or substituted Makes phenols commercially attractive. The use of the catalysts can additionally reduce the amount of during the Decrease in the decomposition reaction formed, high molecular weight by-products. Likewise, they need to carry out the Decomposition containers used not to consist of such corrosion-resistant materials as required when acidic catalysts are used, since the catalysts are by their nature not strongly acidic, and there is therefore no need to remove the catalysts prior to recovery of the phenols, although this is done if so desired, can be carried out.

According to the present invention there is a method of making of a phenol or a substituted phenol by decomposition of a secondary aromatic organic Hydroperoxide created, which allows the implementation of the decomposition in the presence of a catalyst that contains a compound the at least one metal atom or one cation or at least one non-metallic cation and at least one Contains connection part, which differs from an anion of the general formula I.

Il _

X-S (I)

609848/1132

ORIGINAL INSPEGT5D

2 5? Π 1 21st

derives, in which S is a sulfur atom, Y is a sulfur or oxygen atom, or a group of the general formula

V-R ¹

Il

denotes in which V is a nitrogen or phosphorus atom and R ^{1 is} a hydrogen atom or a substituted or unsubstituted hydrocarbyl group, and X is a group of the general formula

? Il Il Il

R — ν — C—, RO — C— or RO — P—

OR

represents in which each radical R is substituted or unsubstituted Hydrocarbyl group, preferably having 1 to 12 carbon atoms, and obtaining the desired Phenol or substituted phenol from the decomposition product. The catalyst preferably contains because of the Ease with which such connections are made, a connection as defined above in which Y is a sulfur atom.

Examples of unsubstituted hydrocarbyl groups R and R ¹ are alkyl groups (both straight and branched chain), aryl groups (including alkaryl groups) and aralkyl groups such as benzyl groups. Preferred alkyl groups are those having 1 to 8 carbon atoms, such as

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" ⁶ " 2 5? η 121

for example methyl, ethyl, propyl, isopropyl, n-butyl, Isobutyl, tert-butyl, aryl, heptyl and oxyl groups, and preferably those having 1 to 4 carbon atoms.

Examples of non-metallic cations include ammonium ions (NRj,) where each R is hydrogen or a like is the group defined above.

Examples of substituted hydrocarbyl groups are hydrocarbyl groups, for example those listed above, which are replaced by one or more halogen atoms, alkoxy groups, the preferably contain from 1 to 6 carbon atoms, or nitro groups are substituted.

The catalyst preferably contains a compound of a transition metal, in particular a compound of transition metals of groups VIII, Ib or Hb of the Periodic Table of the Elements, although compounds of metals that non-transition metals such as tin or antimony can also be used.

For example, the catalyst can contain a compound which is at least one of an anion of those defined above general formula I derivable connection part and at least one metal atom selected from iron, cobalt,

- 7 -509848/1132

252-121

Nickel, palladium, copper, silver, zinc, cadmium, mercury, tin and antimony atoms.

The structure of the metal compound used as a catalyst in the process of the present invention depends of course on the identity of the metal and the groups X and Y. For example, the compounds can be complexes as indicated by the following general formula II

(ID

are reproduced, in which M the metal and N the oxidation state of the metal, or they can be a Be compound that is salt-like in nature, as indicated by the following formula III

N +

(III)

is reproduced, in which N has the meaning given above.

509848/113 2

5 2 0121

It is believed that the compounds form a polymeric structure with certain metals, such as, for example by the following formula IV

- - (IV)

is reproduced.

For example, the compounds can consist of linear chains of metal atoms and ligands, or of chains of metal atoms and ligands which form a three-dimensional polymer exist.

Accordingly, it can be seen that the connecting portions which can be derived from the anion of the general formula I are the ligand portion a complex or the anionic part of a salt.

Representative examples of the classes of catalysts that can be used in the process of the invention are Metal-N-disubstituted mono- and dithiocarbamates of the general Formulas V and VI

'N - C

^M and

N-C

S "

: m

(V)

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(VI)

where M is the metal, N is the oxidation state of the metal and R has the same meaning as above; Metal xanthates of the general formula VII

(VII)

where M is the metal, N is the oxidation state of the metal and R has the same meaning as above; and metal disubstituted Di- and monothiophosphates of the general formulas VIII and IX

(VIII)

(IX)

where M is the metal, N is the oxidation state of the metal and the remainder R has the same meaning as above.

- 10 -

509848/1 132

Particularly preferred catalysts are compounds of the general formulas V, VI, VII, VIII and IX, in which each Group R denotes an alkyl group, in particular the alkyl groups expressly mentioned above.

It has surprisingly been observed that when using the process according to the invention, increased phenol yields can be achieved by decomposition of secondary aromatic organic hydroperoxides compared to conventionally used acidic catalysts. Thus, yields can, for example, from about 80 wt -.% Of phenol by decomposition of Äthylbenzolhydroperoxid according to the methods of the invention are achieved. In addition, significantly lower amounts of high molecular weight by-products are formed compared to the use of conventional acid catalysts.

The secondary aromatic organic hydroperoxide used as a starting material in the process of the present invention can be an arylmonoalkylhydroperoxide, which is preferably from 2 to 24, particularly preferably from 2 to 16 and with particularly advantageous 2 to 12 carbon atoms in the alkyl part contains. An example of such a hydroperoxide is ethylbenzene hydroperoxide. Optionally, a substituted Arylalkyl! Hydroperoxide can be used, i.e. a hydroperoxide, in which the aryl group has one or more substituents

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2 5? η 1 21

tuenten, e.g. selected from halogen atoms and alkyl, alkoxy and nitro groups. The decomposition of such hydroperoxides supplies an appropriately substituted phenol. In a further alternative, a dialkylaryldihydroperoxide can be used can be used, i.e. a compound having an aryl nucleus formed by two secondary alkyl hydroperoxide groups is substituted, in which case the decomposition gives a compound having two phenolic hydroxyl groups will. Such hydroperoxides can also carry one or more substituents, which makes it possible accordingly to produce substituted phenolic compounds with two phenolic OH groups.

The decomposition of the hydroperoxide in the presence of the catalyst proceeds very smoothly and can under a wide range varied reaction conditions take place. The reaction temperature is preferably not allowed to rise too high, since this does so to the thermally initiated decomposition of the hydroperoxide with the formation of undesirable by-products and in an extreme Case could lead to rapid and uncontrollable, and possibly explosive, decomposition. It will a reaction temperature in the range from room temperature to 180 ° C. is preferred, in particular in the range from room temperature up to 150 ° C and particularly advantageously in the range from 100 ° C to 140 ° C. The decomposition of the hydroperoxide can be exothermic

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be that it is desirable to control the reaction temperature in order to keep it at a desired level. to Conventional techniques such as external cooling and / or regulation can be used for this purpose the rate at which the hydroperoxide is brought into contact with the catalyst.

Preferably, the aldehyde coproduct of the decomposition is continuously removed during the decomposition reaction the possibility of undesirable side reactions between the aldehyde and other components of the decomposition product to reduce. For example, the aldehyde can be distilled off and collected in a cooler. The distance of the aldehyde can be assisted by conducting the decomposition under reduced pressure, but is generally the pressure at which the decomposition is carried out is not very critical and it may conveniently be more atmospheric Pressure may be applied, particularly in the case where the aldehyde coproduct is sufficiently volatile at the reaction temperature to be distilled off at atmospheric pressure to become.

The time required to complete the reaction will depend, among other things, on the reaction temperature, however it is normal even at very low reaction temperatures

- 13 509848/1 1 32

sometimes not more than 3 or 4 hours. at
Preferred reaction temperatures, the decomposition will in most cases not usually occur within, for example, 5 to 50 minutes at 150 ° C., or within 1.5 to 2 hours
longer than 1 hour, at 80 ° C to 120 ° C.

In order to moderate the decomposition, the process according to the invention is usually carried out in the presence of an inert solvent, ie a solvent which does not react with the
Hydroperoxide or its decomposition products react. Accordingly, in the case where a hydroperoxide is solid at the reaction temperature, it is preferred to dissolve it in an inert solvent. The inert solvent can also be used, if desired, when the hydroperoxide is liquid at the reaction temperature employed. If
If an inert solvent is used, it is preferably present in such an amount that the solution contains from 1% by weight to 50% by weight , particularly preferably from 5% by weight to 25% by weight, of hydroperoxide. Examples of inert solvents include benzene, toluene, xylene, ethylbenzene, chlorobenzene and nitrobenzene.

Very small amounts of catalyst can be used in the process according to the invention can be used with success. Larger amounts can also be used. However, this is not

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25? Ni21

necessary and only leads to an increase in costs, and in some cases even larger amounts of catalyst can be used be harmful. In a preferred embodiment of the In the present invention, the ratio of catalyst to hydroperoxide is 1: 10,000 to 1: 1,000, preferably 1: 5000 to 1: 1000.

The hydroperoxides used in the process according to the invention can be prepared by the usual processes, such as, for example, by autoxidation of an alkylaryl compound. The alkylaryl starting materials for autoxidation can also by customary processes, such as, for example, by alkylation of aryl compounds with a Olefin.

The phenol and aldehyde produced according to the process of the invention can be recovered by conventional methods be, for example by fractional distillation, and it can generally those catalyzed in the conventional acid Purification techniques applied are used, although the procedural steps that deal with the process Catalyst removal deal, of course, can be omitted.

The invention is now illustrated by the following examples

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explained in more detail.

example

0.0025 parts by weight bis (diethyldithiocarbamato) cobalt (II) (Molecular weight 355.5) was weighed into a pressure vessel made of glass and dissolved in 25 parts by weight of ethylbenzene.

3 parts by weight of ethylbenzene hydroperoxide (molar ratio of ethylbenzene hydroperoxide to catalyst = 3000: 1) were

added and the pressure vessel closed.

The reactor was in an oil bath maintained at 120 ° C for 30 minutes using a magnetic

Fellow traveler stirred.

The contents were cooled and added to residual hydroperoxide

and phenol analyzed.

The following analysis results were obtained:

Residual hydroperoxide 0.03 parts by weight Phenol produced 1.62 parts by weight

Percent Conversion 99.0 % Selectivity to Phenol 82.7 %

Examples 2 to 14

The procedure of Example 1 was repeated using various catalysts and the results set out in the table below.

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O? a b e 1 1 e

example

catalyst

Molecular weight.

Parts by weight

of the catalyst

Ratio of residue

Ethylbenzene hydro-

peroxide to cata- peroxide

lyser (parts by weight)

Produ- Um- % Dissected wand- lekti-Phenol lung vity (parts by weight) {%) for

phenol

CD CO-P-OO

2 Tris (diethyldithio-
carbamato) iron (III) 500.6 0.0034 3115: 1 0.14 1.19 95.2 63.0 3 Bis (diethyldithiocar-
bamato) nickel (II) 355.3 0.0025 3000: 1 0.04 1.50 98.6 76.9 4th Bis (diethyldithio-
phosphato) nickel (II) 429.1 0.0030 2984: 1 0.01 1.67 99.9 84.0 Ul Bis (äthylxanthato) -
nickel (II) 301.1 0.0021 2976: 1 0.15 1.24 94.8 66.5 6th Bis (diethyldithio-
carbamatο) copper (II) 360.1 0.0025 2963: 1 0.02 1.52 99.3 77.2 7th Bis (dibenzyldithio-
carbamato) zinc (II) 554 0.0044 2655: 1 0.03 1.59 99.0 81.0 8th Bis (diethyldithio-
carbamate ο) palladium (II) .402.9 0.0028 2966: 1 0.07 1.43 97.6 74.1

Table (continued)

Molecular weight ratio of residue to product to % Se largew. Parts of ethylbenzene hydro- dous hydrogenated convertible peroxide to cata- oxide phenol development vity of catalyst (parts by weight) (parts by weight) {%) for

phenol

example
No.

catalyst

SaSnbeSm , 56 ,1 0.0018 3OOO: 1 1 . " 0 , 53 .9.8 53.5 10 521 , 9 0.0037 3026: 1 ⁰ , 03 ¹ , 61 99.0 81.6 11 Bis (diethyldithiocarba—
matο) mercury (II) - ¹ 0.0035 3005: 1 ⁰ , 02 ¹ , 67 99.3 84.8 12th Bis (diethyldithio-
c arb amat ο ) ζ inn (XIj 415 , 2 0.0026 3367: 1 0 , 03 1 , 66 99.0 84.6 13th Tetrakis (diethyldithio-
carbamato) tin (IV) 711 , 7 0.0051 2939 ' 1 0 , 03 1 , 49 99.0 75.8 14th Tris (diethyldithio-
carbamato) antimony (III) ⁵⁶⁶ ■ ⁵ 0.0039 3045 ' 1 0 , 01 1 , 58 99.7 79.5

Claims (14)

Claims ll Process for the preparation of a phenol or a substituted phenol by decomposition of a secondary aromatic hydroperoxide, characterized that the decomposition in the presence of a catalyst which contains a compound that at least contains a metal atom or a cation or at least one non-metallic cation and at least one connecting part, which differs from an anion of the general formula I X — S "(I) derives, in which S is a sulfur atom, Y is a sulfur or oxygen atom, or a group of the general formula V-R ¹ Il denotes in which V is a nitrogen or phosphorus atom and R ^{1 is} a hydrogen atom or a substituted or unsubstituted hydrocarbyl group, and X is a group of the general formula ? Ii Il Il R — N — C—, RO — C— or RO — P— OR represents in which each radical R is substituted or unsubstituted Hydrocarbyl group, performs, and that - 19 509848/1132 ORIGINAL INSPECTED 2 5? π 1 21 desired phenol or substituted phenol from the decomposition product wins. 2. The method according to claim 1, characterized in that the catalyst is a metal-N-disubstituted Contains mono- or dithiocarbamate. 3. The method according to claim 1, characterized in that the catalyst contains a metal xanthate. 4. The method according to claim 1, characterized that the catalyst contains a metal disubstituted di- or monothiophosphate. 5. The method according to any one of claims 1 to 4, characterized in that the metal is a transition metal. 6. The method according to claim 5 _S, characterized in that the metal is a transition metal from groups VIII ₃ Ib or Hb of the Periodic Table of the Elements. 7. The method according to any one of claims 1 to 4, d a - - 20 809848/1132 characterized in that the catalyst contains a compound which can be derived from an anion of the general formula I defined above Connection part and at least one metal atom selected from iron, cobalt, nickel, palladium, copper, Contains silver, zinc, cadmium, mercury, tin and antimony atoms. 8. The method according to any one of claims 1 to 7 *, characterized in that the aromatic hydroperoxide is an aryl monoalky! Hydroperoxide with 2 to 2k carbon atoms in the alkyl part. 9. The method according to claim 8, characterized in that the monoalkyl hydroperoxide in the alkyl part contains from 2 to 12 carbon atoms. 10. The method according to claim 9> characterized that the aromatic hydroperoxide is ethylbenzene hydroperoxide. 11. The method according to any one of claims 1 to 10, characterized in that the decomposition at a temperature in the range from room temperature to 180 ° C is carried out. - 21 - 509848/1132 12. The method according to any one of claims 1 to 11, characterized in that the decomposition is carried out in the presence of an inert solvent. 13 · Method according to one of Claims 1 to 12, characterized in that the ratio from catalyst to hydroperoxide is in the range from 1:10 to 1: 1000. 14. The method according to claim 13 » characterized in that the ratio of catalyst to hydroperoxide is in the range from 1: 5000 to 1: 1000. 509848/1 132